1. Field of the invention
The present invention concerns a blade array for turbomachines comprising blades disposed between an inner wall and an outer wall and in which the inner wall and/or the outer wall is provided with a suction port near at least some blades, said port having a first end situated along the upper surface in a region of the blade extending from the point of maximum curvature to the neck of the passage between said blade and the adjacent blade.
Suction ports have been provided in the inner and/or outer wall of such blade arrays to aspirate the boundary layers along the inner and outer wall. Disturbances occur in these layers. See for example the article "Sur les pertes a l'extremite des aubes de turbine" published in the Brown, Boveri journal in French, November 1941, pages 356 through 361 and in particular FIGS. 2 and 3.
These disturbances are accompanied by significant losses known as secondary losses which affect the efficiency of a blade array in inverse proportion to the blade height/chord ratio.
The Japanese document JP-A-52-54807 published 4 May 1977 describes one example of a blade array with suction ports.
The known ports cross the inter-blade passage and extend from the upper surface of one blade to the lower surface of the adjacent blade.
It has been found that these ports do not achieve any improvement and even increase the losses.